In reply to Tyler:
We have 3 house cats and one that comes and goes.
3 Tom's and 1 female.
Scratching? Yes, all of them scratch just about everything they can despite scratching posts all over the house.
Smell? A tiny bit but good housekeeping keeps it away.
Hair? All 4 are general moggies, 3 hardly shed at all but one is a furry demon, he sleeps on the landing and you can clean the burgundy carpet in the morning and it looks like a white blanket by teatime.
Pee? Of the 3 house cats 2 only ever use the tray but 1 despite being neutered has spent the last 10 years spraying round the house on walls, carpet and furniture and yes it stinks.
Poo, the only one that poo's outside of the tray is the outdoor cat, occasionally he will hide in the house when we go out and sometimes we come back to a nice surprise, he will not ever use the litter tray because the others gang up on him when he goes in to the cupboard to use it.
We also rented a house to a family member with 2 house cats, they pissed everywhere and when she moved out I had to replace every carpet and underlay it took around 2 weeks of bleaching the floorboards twice a day to get rid of the smell.
That said my new tennents keep a very clean and tidy house and approached me late last year about the no pets clause in the lease and they now have a cracking little kitten.
I will take a good tennent with a cat over a bad tennent anyday.